Before writing this article, I knew two things about gasoline (and one of them I have kept as a well-guarded secret until now). First, gas is used in combustion engines, such as cars and boats with motors—aka pontoons. Second, I belong to that weird club that secretly loves the smell of gasoline.

Yes, I know it is incredibly dangerous to sniff gas, so I promise I only enjoy this guilty pleasure while filling up my soccer-mom van. But what I didn’t know was why gasoline degrades and therefore needs fuel additives and cleaning treatments, as well as the less-useful (albeit interesting) tidbit about why some people find the smell of gasoline pleasant.

The Whys & What-Have-Yous

Both answers have to do with the rather obvious fact that gasoline is a cocktail of chemicals. Made of more that 150 different chemical compounds called hydrocarbons, it also contains even more chemicals to act as lubricants, anti-rust agents, and anti-icing agents to improve your engine’s performance. Not a healthy stew (for humans) by any measure, but just what a combustion engine needs.

It stands to reason that such a toxic soup would have a short shelf life, especially with environmental factors such as heat, humidity, and oxygen. It matters how gas is stored (plastic, air-tight containers are best) but in any situation, gas will still degrade over time. These changes in the fuel’s chemical properties can damage engine components and even start to form a gum residue and engine blockages. In as little as three to six months, gas becomes less combustible. Also, fuel with ethanol can draw water vapor into your fuel line, which could result in internal corrosion.

Here’s the good news: if you add a fuel stabilizer, it will not only clean and lubricate engine components such as fuel pumps and carburetors, but also lengthen the shelf life of the gas to one to three years. This is helpful when the boating season is long and you don’t always use a full tank with every adventure. It also comes in handy for winterization since you don’t have to empty your gas tank or worry about the fuel in it degrading over the off-season.

Keep your fuel fresh (not just smelling great) with two kinds of products: an additive to use during the season, and a stabilizer for the winter. Here are three well-known brands with great products to get you started.

GAS-SHOK From USA Fuel Service

GAS-SHOK Plus Water Absorber & Fuel Stabilizer is a multi-function fuel additive for use in two- and four-stroke engines that keeps fuel fresh for 12–18 months. The broad-spectrum formula provides everything needed to keep your boat starting easily and running smoothly, including a water-dispersant, stabilizer, lubricant, cleaner, and combustion enhancer.

GAS-SHOK Plus doesn’t contain alcohol or acids, so it won’t damage hoses, gaskets, or other components. Used regularly, it keeps the fuel system clean by preventing gum and varnish from accumulating on rings, valves, and related parts. Plus, the advanced formula adds lubrication to extend the life of the fuel pump and injectors. These attributes translate into better mileage and an engine that runs as smooth as silk. GAS-SHOK Plus can be added to the fuel tank at the rate of one ounce per 10 gallons of gasoline. Also ideal for winterizing, it has no impact on engine warranties. Remember to fill your tank to 90 percent capacity to prevent excess water condensation buildup during winter storage.

STA-BIL From Gold Eagle

With two additives that are engineered to combat the effects of the harsh marine environment, STA-BIL’s in-season treatment and storage treatment both have properties to prevent corrosion, remove water, and stabilize your fuel.

STA-BIL 360 Marine is an in-season fuel treatment meant to be added at every fill-up when you are utilizing an engine. This additive contains fuel system cleaners, corrosion inhibitors, extra water removers, and stabilizers to make sure your engine continues running smooth and healthy all season long. This complete season fuel system cleaner has corrosion control, removes water, and can be used every time you fill up. Just 1 ounce of additive treats 10 gallons of gasoline.

For the off-season, STA-BIL Storage eliminates the need to drain your fuel during storage since it will keep gasoline fresh for two years. It also prevents corrosion within the fuel system. With STA-BIL’s patented measure chamber bottle, it’s easy to dose the exact amount needed for any tank size; 1 ounce of additive treats 2.5 gallons of gasoline.

Techron Marine From Chevron

A powerful fuel additive, Techron helps fight deposits in an engine’s fuel intake system and minimizes harmful combustion chamber deposits. This helps optimize performance, minimize emissions, restore lost power, and maximize fuel economy. Ten times more concentrated than Chevron with Techron at the fuel pump, the Techron additive provides a quicker cleanup of intake valve deposits left by lower quality gasoline.

By combining corrosion protection with fuel stability and detergency for cleaning power, Techron Marine is a deep clean for your fuel system, and it is best used every three months. Techron Marine also contains fuel stabilizers to keep fuel fresh for up to two years. For best practice, pour the recommended treatment of Techron into a nearly empty tank, then top off the tank with quality fuel. This helps to facilitate mixing and maximize effectiveness. If your tank is half or all the way full, it is best to wait until your next fill-up.

Back To That Smell

So why do some of us love the smell of gasoline? There’s a real reason. The magic ingredient is the chemical benzene, which increases octane levels to improve not just engine performance but also fuel efficiency. And it just so happens that benzene has a naturally sweet smell that most noses are particularly sensitive to. In fact, it’s so pungent that the human nose can detect it if there’s just one part per million in the air that we breathe. It also evaporates rapidly enough to be smelled instantly.

Since benzene has a pleasing scent, it was used during the 1800s and early 1900s in after-shaves and other personal products to give them a sweet aroma…until it was discovered that benzene is a carcinogen and dangerous when inhaled in high concentrations. What a killjoy.

It’s also thought that benzene has an actual physical effect on the nerve receptors that detect smell. When benzene and other hydrocarbons are inhaled, they suppress the nervous system and result in a temporary, euphoric feeling. You know, like drugs. Unsurprisingly, gasoline is a commonly abused inhalant with devastating health effects. So please, do NOT intentionally sniff gasoline.

However, there are wonderful benefits to using fuel additives to your gas tank during boating season and fuel stabilizers during winter storage: better engine performance, preserved fuel quality, and less fuel evaporation with better combustion.